libip6t_REJECT.c revision 73866357e4a7a0fdc1b293bf8863fee2bd56da9e 
1/* Shared library add-on to ip6tables to add customized REJECT support.
2 *
3 * (C) 2000 Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
4 *
5 * ported to IPv6 by Harald Welte <laforge@gnumonks.org>
6 *
7 */
8#include <stdbool.h>
9#include <stdio.h>
10#include <string.h>
11#include <stdlib.h>
12#include <getopt.h>
13#include <xtables.h>
14#include <linux/netfilter_ipv6/ip6t_REJECT.h>
15
16struct reject_names {
17	const char *name;
18	const char *alias;
19	enum ip6t_reject_with with;
20	const char *desc;
21};
22
23static const struct reject_names reject_table[] = {
24	{"icmp6-no-route", "no-route",
25		IP6T_ICMP6_NO_ROUTE, "ICMPv6 no route"},
26	{"icmp6-adm-prohibited", "adm-prohibited",
27		IP6T_ICMP6_ADM_PROHIBITED, "ICMPv6 administratively prohibited"},
28#if 0
29	{"icmp6-not-neighbor", "not-neighbor"},
30		IP6T_ICMP6_NOT_NEIGHBOR, "ICMPv6 not a neighbor"},
31#endif
32	{"icmp6-addr-unreachable", "addr-unreach",
33		IP6T_ICMP6_ADDR_UNREACH, "ICMPv6 address unreachable"},
34	{"icmp6-port-unreachable", "port-unreach",
35		IP6T_ICMP6_PORT_UNREACH, "ICMPv6 port unreachable"},
36	{"tcp-reset", "tcp-reset",
37		IP6T_TCP_RESET, "TCP RST packet"}
38};
39
40static void
41print_reject_types(void)
42{
43	unsigned int i;
44
45	printf("Valid reject types:\n");
46
47	for (i = 0; i < ARRAY_SIZE(reject_table); ++i) {
48		printf("    %-25s\t%s\n", reject_table[i].name, reject_table[i].desc);
49		printf("    %-25s\talias\n", reject_table[i].alias);
50	}
51	printf("\n");
52}
53
54static void REJECT_help(void)
55{
56	printf(
57"REJECT target options:\n"
58"--reject-with type              drop input packet and send back\n"
59"                                a reply packet according to type:\n");
60
61	print_reject_types();
62}
63
64static const struct option REJECT_opts[] = {
65	{.name = "reject-with", .has_arg = true, .val = '1'},
66	XT_GETOPT_TABLEEND,
67};
68
69static void REJECT_init(struct xt_entry_target *t)
70{
71	struct ip6t_reject_info *reject = (struct ip6t_reject_info *)t->data;
72
73	/* default */
74	reject->with = IP6T_ICMP6_PORT_UNREACH;
75
76}
77
78static int REJECT_parse(int c, char **argv, int invert, unsigned int *flags,
79                        const void *entry, struct xt_entry_target **target)
80{
81	struct ip6t_reject_info *reject =
82		(struct ip6t_reject_info *)(*target)->data;
83	unsigned int i;
84
85	switch(c) {
86	case '1':
87		if (xtables_check_inverse(optarg, &invert, NULL, 0, argv))
88			xtables_error(PARAMETER_PROBLEM,
89				   "Unexpected `!' after --reject-with");
90		for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
91			if ((strncasecmp(reject_table[i].name, optarg, strlen(optarg)) == 0)
92			    || (strncasecmp(reject_table[i].alias, optarg, strlen(optarg)) == 0)) {
93				reject->with = reject_table[i].with;
94				return 1;
95			}
96		xtables_error(PARAMETER_PROBLEM, "unknown reject type \"%s\"", optarg);
97	}
98	return 0;
99}
100
101static void REJECT_print(const void *ip, const struct xt_entry_target *target,
102                         int numeric)
103{
104	const struct ip6t_reject_info *reject
105		= (const struct ip6t_reject_info *)target->data;
106	unsigned int i;
107
108	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
109		if (reject_table[i].with == reject->with)
110			break;
111	printf(" reject-with %s", reject_table[i].name);
112}
113
114static void REJECT_save(const void *ip, const struct xt_entry_target *target)
115{
116	const struct ip6t_reject_info *reject
117		= (const struct ip6t_reject_info *)target->data;
118	unsigned int i;
119
120	for (i = 0; i < ARRAY_SIZE(reject_table); ++i)
121		if (reject_table[i].with == reject->with)
122			break;
123
124	printf(" --reject-with %s", reject_table[i].name);
125}
126
127static struct xtables_target reject_tg6_reg = {
128	.name = "REJECT",
129	.version	= XTABLES_VERSION,
130	.family		= NFPROTO_IPV6,
131	.size 		= XT_ALIGN(sizeof(struct ip6t_reject_info)),
132	.userspacesize 	= XT_ALIGN(sizeof(struct ip6t_reject_info)),
133	.help		= REJECT_help,
134	.init		= REJECT_init,
135	.parse		= REJECT_parse,
136	.print		= REJECT_print,
137	.save		= REJECT_save,
138	.extra_opts	= REJECT_opts,
139};
140
141void _init(void)
142{
143	xtables_register_target(&reject_tg6_reg);
144}
145